Tautomeric catalysts--molecules that repeatedly cycle between two or more tautomeric states during the course of catalyzing a chemical reaction--are among the few organic catalysts that have been shown to exhibit the phenomenon of bifunctional catalysis. Since the suggestion that tautomeric catalysis may be an important catalytic mechanism both in chemistry and in biochemistry is a recent one, many opportunities exist to explore both its scope and depth. We are continuing extensive studies of Knoevenagel reaction between cinnamaldehyde and malononitrile in benzene at 25 degrees C. We shall initiate studies of the trifluoroacetylation of 4-nitrophenol and will search for new examples of tautomeric catalysis in non-polar solvents that might bear upon certain aspects of enzyme mechanisms. We shall explore the principle of chemically anchored catalysts as a kinetic tool in the determination of reaction mechanisms.